WO2017204135A1

WO2017204135A1 - Ink jet recording apparatus

Info

Publication number: WO2017204135A1
Application number: PCT/JP2017/018969
Authority: WO
Inventors: 剛浦上
Original assignee: コニカミノルタ株式会社
Priority date: 2016-05-27
Filing date: 2017-05-22
Publication date: 2017-11-30
Also published as: US10471748B2; JPWO2017204135A1; JP6981406B2; US20190143721A1

Abstract

Provided is an ink jet recording apparatus capable of suppressing a fluctuation of a distance between a nozzle surface and an outer peripheral curved surface of a conveyance drum. The ink jet recording apparatus is provided with: a conveyance unit that rotates the conveyance drum about a cylindrical shaft to convey a recording medium on the outer peripheral curved surface of the conveyance drum; a head unit (24) having nozzles that eject ink; an attachment member (212) of which a relative position to the cylindrical shaft is fixed and to which the head unit (24) is attached with the outer peripheral curved surface of the conveyance drum and opening parts of a nozzle surface on which the opening parts of the nozzles are formed in the head unit facing each other at a prescribed relative distance; a fixing member (70) that fixes a fixing portion positioned between the center of gravity of the head unit and the cylindrical shaft to the attachment member in a direction perpendicular to the cylindrical shaft within a horizontal plane in the head unit; and a support member (90) that applies a force in a direction in which rotation due to the gravity of the fixed head unit is disturbed to the head unit to support the same.

Description

Inkjet recording device

The present invention relates to an ink jet recording apparatus.

Conventionally, ink is ejected from a nozzle by a head unit in which nozzles are arranged over the recording width of an image in a width direction orthogonal to the recording medium conveyance direction on the recording medium conveyed by the conveyance unit, and the recording is performed. There is an ink jet recording apparatus that records an image on a medium. Some of such inkjet recording apparatuses record a color image using a plurality of head units that respectively eject a plurality of different color inks from nozzles.

In addition, as one of the conveyance units, there is a type in which a recording medium is placed on an outer peripheral curved surface of a cylindrical conveyance drum and the recording medium is conveyed by rotating the conveyance drum around a cylindrical axis. Patent Document 1 discloses an ink jet recording apparatus that records an image using such a transport unit and a plurality of head units. In this ink jet recording apparatus, a plurality of head units are arranged radially from the cylindrical shaft of the transport drum so that the nozzle surface provided with the nozzle opening in each head unit faces the outer peripheral curved surface of the transport drum in a substantially parallel state. Are inclined to each other. Further, in the ink jet recording apparatus of Patent Document 1, the head unit has two fixing portions in the vicinity of both longitudinal ends of the bottom surface provided with the nozzle surface fixed to a predetermined mounting member.
With such an arrangement, it is possible to reduce the variation in the distance between the opening of each nozzle on the nozzle surface and the outer peripheral curved surface of the transport drum, so that the ink ejected from each nozzle is on the recording medium that is transported. Can be landed at the proper position.

JP 2013-248887 A

However, in the conventional ink jet recording apparatus, since the head unit is inclined, the center of gravity of the head unit and the fixed portion located near the nozzle surface of the head unit are aligned with the cylindrical axis in the horizontal plane. The vertical horizontal distance direction is shifted. In such a head unit in which the center of gravity and the fixed part are displaced in the horizontal distance direction, a moment to rotate the head unit is generated due to gravity, which may cause the head unit to tilt or bend. . As a result, there is a problem in that the distance between the nozzle surface and the outer peripheral curved surface of the transport drum varies, and the landing position of the ink ejected from the nozzle deviates from the appropriate position and the image quality of the recorded image decreases.

An object of the present invention is to provide an ink jet recording apparatus capable of suppressing fluctuations in the distance between the nozzle surface and the outer peripheral curved surface of the transport drum.

In order to achieve the above object, the invention of the ink jet recording apparatus according to claim 1 comprises:
A transport unit that has a cylindrical transport drum, the recording medium is placed on an outer peripheral curved surface of the transport drum, and transports the recording medium by rotating the transport drum around a cylindrical axis;
A head unit having a nozzle for discharging ink to the recording medium to be conveyed;
The relative position with respect to the cylindrical shaft is fixed, and the outer peripheral curved surface of the transport drum and the opening on the nozzle surface where the opening of the nozzle is provided in the head unit face each other with a predetermined relative distance. An attachment member to which the head unit is attached;
In the head unit, a fixing member that fixes a fixing portion located between the center of gravity of the head unit and the cylindrical shaft in a horizontal plane in a direction perpendicular to the cylindrical shaft, to the mounting member;
A support member that supports the head unit by exerting on the head unit a force in a direction that prevents rotation of the head unit fixed to the mounting member due to gravity;
It is characterized by having.

According to a second aspect of the present invention, in the ink jet recording apparatus according to the first aspect,
The support member supports the head unit by exerting a force in a direction that prevents the rotation on the head unit at a position farther from the cylindrical shaft than the fixed portion.

The invention according to claim 3 is the ink jet recording apparatus according to

claim

1 or 2,
The nozzle surface is provided with a plurality of nozzle openings over a predetermined recording width in the cylinder axis direction along the cylinder axis,
The ink jet recording apparatus
In the head unit, in the head unit, the first fixing member that fixes the first fixing portion positioned on one side of the arrangement range of the plurality of nozzles in the cylindrical axis direction to the mounting member; The second fixing member that fixes the second fixing portion located on the other side of the arrangement range of the plurality of nozzles in the cylindrical axis direction with respect to the mounting member;
The support member supports the head unit by exerting a force on a position between the first fixed portion and the second fixed portion in the cylindrical axis direction of the head unit.

The invention according to claim 4 is the ink jet recording apparatus according to any one of claims 1 to 3,
The nozzle surface is provided with a plurality of nozzle openings over a predetermined recording width in the cylinder axis direction along the cylinder axis,
The openings of the plurality of nozzles are opposed to a plurality of different positions in the conveyance direction of the recording medium on the outer peripheral curved surface.

The invention according to claim 5 is the inkjet recording apparatus according to any one of claims 1 to 4,
The head unit is
A recording head having the nozzle surface;
A substrate on which the recording head is fixed;
With
The recording head is fixed to the substrate with the nozzle surface exposed from one surface of the substrate,
The fixing member is characterized in that the fixing portion provided on the one surface of the substrate is fixed to the mounting member.

A sixth aspect of the present invention is the ink jet recording apparatus according to the fifth aspect,
The head unit has a housing provided on the side opposite to the one surface of the substrate,
The support member supports the head unit by exerting a force on the casing.

The invention according to claim 7 is the inkjet recording apparatus according to claim 6,
The case is characterized in that an ink tank for storing ink supplied to the recording head is accommodated in the casing.

The invention according to claim 8 is the inkjet recording apparatus according to any one of claims 1 to 7,
In the support member, a relative position of the first part of the support member with respect to the cylindrical shaft is fixed, and a second part different from the first part is fixed to the head unit, The head unit is supported by a tensile stress generated between the part and the second part.

The invention according to claim 9 is the ink jet recording apparatus according to claim 8,
A holding portion capable of holding the head unit at a predetermined relative position with respect to the cylindrical shaft at least in a state where the fixing of the head unit by the fixing member to the mounting member is released;
The first part is attached to the holding part.

The invention according to claim 10 is the inkjet recording apparatus according to claim 6 or 7,
A combination member combined with the substrate; and a frame member provided integrally with the combination member and positioned above the casing in the vertical direction, and at least the head by the fixing member with respect to the attachment member A holding unit capable of holding the head unit at a predetermined relative position with respect to the cylindrical axis by supporting the substrate by the combination member in a state in which the unit is released;
The support member has a first position in the support member fixed to the frame member of the holding portion so that a relative position to the cylindrical shaft is fixed, and a second position different from the first position A part is fixed to the casing, and the head unit is supported by a tensile stress generated between the first part and the second part.

The invention according to claim 11 is the ink jet recording apparatus according to any one of claims 8 to 10,
The support member includes an elastic body that generates the tensile stress according to a force received from the first part and the second part.

The invention according to claim 12 is the inkjet recording apparatus according to claim 11,
A plurality of the head units;
A plurality of the supporting members corresponding to the plurality of head units;
With
In the plurality of support members, the elastic body having a larger longitudinal elastic coefficient as the support member corresponding to the head unit in which the mounting method is such that a large moment for inducing the rotation of the head unit due to gravity is applied to the mounting member. Is used.

According to the present invention, there is an effect that the variation in the distance between the nozzle surface and the outer peripheral curved surface of the transport drum can be suppressed.

It is a figure which shows schematic structure of an inkjet recording device. It is a schematic diagram which shows the structure of a head unit. It is a block diagram which shows the main function structures of an inkjet recording device. FIG. 3 is a schematic perspective view illustrating a configuration around a transport drum and a head unit in an image forming unit. It is a model perspective view which shows the structure of a carriage. It is a model side view which shows the structure of a carriage. It is a model perspective view which shows the structure of the stay and air cylinder in a carriage. It is a model perspective view which shows the structure of the head unit of the state removed from the air cylinder. It is a figure explaining the fixing mechanism of the head unit by a clamp. It is a figure explaining the fixing mechanism of the head unit by a clamp. It is a figure explaining the fixing mechanism of the head unit by a clamp. It is a schematic side view which shows the state by which the four head units were fixed by the clamp. It is a figure which shows the positional relationship of the nozzle surface of a head unit, and the outer peripheral curved surface of a conveyance drum. It is a figure which shows the positional relationship of the nozzle surface and the outer periphery curved surface of a conveyance drum in case the inclination and bending of a head unit arise by gravity.

Hereinafter, embodiments of the ink jet recording apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an ink jet recording apparatus 1 according to an embodiment of the present invention.
The ink jet recording apparatus 1 includes a paper feeding unit 10, an image forming unit 20, a paper discharge unit 30, and a control unit 40 (FIG. 3). Under the control of the control unit 40, the inkjet recording apparatus 1 conveys the recording medium P stored in the paper feeding unit 10 to the image forming unit 20, and the image forming unit 20 records an image on the recording medium P. The recorded recording medium P is conveyed to the paper discharge unit 30. As the recording medium P, in addition to paper such as plain paper and coated paper, various media capable of fixing ink landed on the surface, such as cloth or sheet-like resin, can be used.

The paper feed unit 10 includes a paper feed tray 11 that stores the recording medium P, and a medium supply unit 12 that conveys and supplies the recording medium P from the paper feed tray 11 to the image forming unit 20. The medium supply unit 12 includes a ring-shaped belt supported on the inside by two rollers, and the recording medium P is removed from the paper feed tray 11 by rotating the roller while the recording medium P is placed on the belt. It is conveyed to the image forming unit 20.

The image forming unit 20 includes a transport unit 21, a delivery unit 22, a heating unit 23, a head unit 24, a fixing unit 25, a delivery unit 26, and the like.

The conveyance unit 21 holds the recording medium P placed on the outer peripheral curved surface 211a (conveyance surface) of the cylindrical conveyance drum 211, and the conveyance drum 211 extends in a direction perpendicular to the drawing in FIG. The recording medium P on the transport drum 211 is transported in the transport direction by rotating around the cylindrical shaft 211b (rotary shaft) of the transport drum. The transport drum 211 includes a claw portion and a suction portion (not shown) for holding the recording medium P on the outer peripheral curved surface 211a. The recording medium P is held on the outer peripheral curved surface 211a by the end being pressed by the claw portion and sucked to the outer peripheral curved surface 211a by the intake portion. The transport unit 21 includes a transport drum motor (not shown) for rotating the transport drum 211, and the transport drum 211 rotates by an angle proportional to the rotation amount of the transport drum motor.

The delivery unit 22 delivers the recording medium P conveyed by the medium supply unit 12 of the paper supply unit 10 to the conveyance unit 21. The delivery unit 22 is provided at a position between the medium supply unit 12 and the conveyance unit 21 of the paper supply unit 10, and picks up one end of the recording medium P conveyed from the medium supply unit 12 by the swing arm unit 221. Then, it is delivered to the transport unit 21 via the delivery drum 222.

The heating unit 23 is provided between the arrangement position of the delivery drum 222 and the arrangement position of the head unit 24, and the recording medium P conveyed by the conveyance unit 21 has a temperature within a predetermined temperature range. Heat P. The heating unit 23 includes, for example, an infrared heater and energizes the infrared heater based on a control signal supplied from the CPU 41 (FIG. 3) to cause the infrared heater to generate heat.

In the head unit 24, the nozzle surface provided with the nozzle opening for ejecting ink is exposed to the outside, and the transport drum is rotated at an appropriate timing according to the rotation of the transport drum 211 holding the recording medium P. An image is recorded by ejecting ink onto the recording medium P from the nozzle opening of the nozzle surface facing the outer peripheral curved surface 211 a of 211. The head unit 24 is arranged such that the opening on the nozzle surface and the outer peripheral curved surface 211a are separated by a predetermined distance. In the ink jet recording apparatus 1 of the present embodiment, four head units 24 respectively corresponding to four color inks of yellow (Y), magenta (M), cyan (C), and black (K) are transported in the recording medium P. They are arranged so as to be arranged at predetermined intervals in the order of Y, M, C, and K colors from the upstream side.
Each head unit 24 constitutes a carriage 60 (FIG. 4) together with the stay 61 (FIG. 4) and the like. However, in FIG. 1, components other than the head unit 24 in the carriage 60 are omitted.

FIG. 2 is a schematic diagram showing the configuration of the head unit 24. FIG. 2 is a plan view of the entire head unit 24 as viewed from the side facing the outer peripheral curved surface 211a of the transport drum 211, that is, the bottom surface side where the nozzle surface 24f is provided.
In the present embodiment, the head unit 24 includes 16 recording heads 242 in which a plurality of recording elements that eject ink are arranged in the cylindrical axis direction of the transport drum 211 (that is, the width direction orthogonal to the transport direction). Each recording element of the recording head 242 includes a pressure chamber for storing ink, a piezoelectric element provided on the wall surface of the pressure chamber, and a nozzle 243. When a driving signal for deforming the piezoelectric element is input to the recording element, the pressure chamber is deformed by the deformation of the piezoelectric element and the pressure in the pressure chamber changes, and ink is ejected from the nozzle 243 communicating with the pressure chamber. Ink discharge operation is performed.
In FIG. 2, the position of the opening of the nozzle 243 is shown on the nozzle surface of the recording head 242. The arrangement direction of the recording elements in each recording head 242 is not limited to the width direction orthogonal to the conveyance direction, and may be a direction that intersects the conveyance direction at an angle other than a right angle.

In the head unit 24, a head module 242M is configured by two recording heads 242 arranged adjacent to each other in the transport direction in such a positional relationship that the nozzles 243 of the recording elements are alternately arranged in the width direction. By arranging the nozzles 243 in this manner, the head module 242M can perform recording at a resolution of 1200 dpi (dots per inch) in the width direction. The eight head modules 242M are provided in a state where the nozzle surfaces 24f of the recording head 242 are exposed from one surface perpendicular to the thickness direction of the substrate 24a, which are respectively mated with the openings provided in the substrate 24a. . Further, the eight head modules 242M are arranged in a staggered pattern so that the ranges in which the ink can be ejected from the nozzles 243 are continuously connected in the width direction, and the arrangement ranges in the width direction partially overlap each other. The line head is constituted by being arranged in the above.

In addition, a pair of engaging portions 80 (first) used for fixing the head unit 24 is provided in the vicinity of both ends in the width direction of the substrate 24a, that is, on one side and the other side with respect to the arrangement range of the nozzle 243 in the width direction. 1 fixing part, 2nd fixing part) are provided. A fixing mechanism of the head unit 24 using the engaging portion 80 will be described later.

The arrangement range in the width direction of the nozzles 243 included in the head unit 24 covers the width in the width direction of an area where an image can be recorded in the recording medium P conveyed by the conveyance belt 13. The head unit 24 is used at a fixed position during image recording, and sequentially ejects ink at different intervals (conveyance direction intervals) to different positions in the conveyance direction according to the conveyance of the recording medium P. Record an image using the single pass method.

As the ink ejected from the nozzle 243 of the recording element, an ink that has a property of changing in a gel or sol state depending on the temperature and being cured by irradiating energy rays such as ultraviolet rays is used.
In this embodiment, ink that is gel-like at room temperature and becomes sol-like when heated is used. The head unit 24 includes an ink tank 24g (FIG. 7B) that stores ink, and an ink heating unit (not shown) that heats ink supplied from the ink tank 24g to the recording head 242. The ink heating unit is a CPU 41. The ink is heated to a temperature that becomes a sol state. The recording head 242 discharges ink that has been heated to form a sol. When the sol-like ink is ejected onto the recording medium P, the ink droplets land on the recording medium P and then spontaneously cool, so that the ink quickly becomes a gel and solidifies on the recording medium P.

The fixing unit 25 has an energy beam irradiation unit arranged across the width in the width direction of the conveyance unit 21, and ultraviolet rays or the like from the energy beam irradiation unit to the recording medium P placed on the conveyance unit 21. The ink ejected on the recording medium P is cured and fixed by irradiating energy rays. The energy beam irradiation unit of the fixing unit 25 is disposed to face the outer peripheral curved surface 211a between the position where the head unit 24 is disposed and the position where the delivery drum 261 of the delivery unit 26 is disposed in the transport direction.

The delivery unit 26 includes a belt loop 262 having an annular belt supported on the inside by two rollers, and a cylindrical transfer drum 261 that transfers the recording medium P from the transport unit 21 to the belt loop 262. The recording medium P transferred from the transport unit 21 onto the belt loop 262 by the transfer drum 261 is transported by the belt loop 262 and sent to the paper discharge unit 30.

The paper discharge unit 30 includes a plate-shaped paper discharge tray 31 on which the recording medium P sent from the image forming unit 20 by the delivery unit 26 is placed.

FIG. 3 is a block diagram showing the main functional configuration of the inkjet recording apparatus 1.
The inkjet recording apparatus 1 includes a heating unit 23, a head unit 24 having a recording head driving unit 241 and a recording head 242, a fixing unit 25, a control unit 40, a transport driving unit 51, an input / output interface 52, a bus. 53 and the like.

The recording head driving unit 241 supplies pixel signals of image data from the nozzles 243 of the recording head 242 by supplying a driving signal for deforming the piezoelectric element according to the image data at an appropriate timing to the recording elements of the recording head 242. An amount of ink corresponding to the value is ejected.

The control unit 40 includes a CPU 41 (Central Processing Unit), a RAM 42 (Random Access Memory), a ROM 43 (Read Only Memory), and a storage unit 44.

The CPU 41 reads various control programs and setting data stored in the ROM 43, stores them in the RAM 42, and executes the programs to perform various arithmetic processes. The CPU 41 controls the overall operation of the inkjet recording apparatus 1.

The RAM 42 provides a working memory space to the CPU 41 and stores temporary data. The RAM 42 may include a nonvolatile memory.

The ROM 43 stores various control programs executed by the CPU 41, setting data, and the like. Instead of the ROM 43, a rewritable nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used.

The storage unit 44 stores a print job (image recording command) input from the external apparatus 2 via the input / output interface 52 and image data of an image to be recorded related to the print job. As the storage unit 44, for example, an HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may be used in combination.

The transport drive unit 51 supplies a drive signal to the transport drum motor of the transport drum 211 based on a control signal supplied from the CPU 41 to rotate the transport drum 211 at a predetermined speed and timing. Further, the transport driving unit 51 supplies a drive signal to a motor for operating the medium supply unit 12, the delivery unit 22, and the delivery unit 26 based on a control signal supplied from the CPU 41, so that the recording medium P is transported. Supply to the unit 21 and discharge from the transport unit 21 are performed.

The input / output interface 52 mediates data transmission / reception between the external device 2 and the control unit 40. The input / output interface 52 is configured by any one of various serial interfaces, various parallel interfaces, or a combination thereof, for example.

The bus 53 is a path for transmitting and receiving signals between the control unit 40 and other components.

The external device 2 is a personal computer, for example, and supplies a print job, image data, and the like to the control unit 40 via the input / output interface 52.

Next, a configuration related to movement and fixation of the head unit 24 in the inkjet recording apparatus 1 will be described.
FIG. 4 is a schematic perspective view illustrating a configuration around the transport drum 211 and the head unit 24 in the image forming unit 20.
FIG. 5 is a schematic perspective view showing the configuration of the carriage 60 including the head unit 24.
FIG. 6 is a schematic side view showing the configuration of the carriage 60 including the head unit 24.

In FIG. 4, the conveyance drum 211, a pair of attachment members 212 provided on both side surfaces of the conveyance drum 211 and fixed to the cylindrical shaft 211 b of the conveyance drum 211, and the nozzle surface 24 f are formed on the outer peripheral curved surface 211 a of the conveyance drum 211. Four head units 24 attached to the attachment member 212 by a pair of clamps 70 (first fixing member and second fixing member) so as to face each other, and a carriage that includes the head unit 24 and is used for moving the head unit 24 60 etc. are drawn.

As shown in FIGS. 4 to 6, the head unit 24 includes a plate-like substrate 24a provided so that the length in the width direction is larger than the width of the outer peripheral curved surface 211a of the transport drum 211, and the substrate 24a. It has eight head modules 242M mated with the provided openings, an upper casing 24b extending in the width direction and spanning the upper part of the head module 242M. The upper casing 24b is supported by support plates 24d provided on both sides in the width direction with respect to the eight head units 24 on the substrate 24a, and an ink tank 24g (FIG. 7B) and an ink heating unit are accommodated therein. Yes. Further, the nozzle surface 24f is exposed from the surface (lower surface) opposite to the upper housing 24b side of the substrate 24a. The weight of the head unit 24 of this embodiment is about 50 kg, and the length in the width direction is about 1 m.

In the head unit 24, a pair of engaging portions 80 (FIGS. 2 and 8) provided outside a region of the lower surface of the substrate 24 a facing the outer peripheral curved surface 211 a of the transport drum 211 are fixed by clamps 70. Is attached to the attachment member 212 in a fixed state. The pair of engaging portions 80 are located on a line parallel to the cylindrical shaft 211b. A mechanism for fixing the head unit 24 by the clamp 70 will be described later.

As shown in FIG. 5, the end portions 24 c at both ends in the width direction of the substrate 24 a are held by a pair of air cylinders 62, and the pair of air cylinders 62 are fixed to the stay 61. The stay 61, the pair of air cylinders 62 and the head unit 24 constitute a carriage 60.

FIG. 7 is a schematic perspective view showing the configuration of each part of the carriage 60. FIG. 7A shows the configuration of the stay 61 and the air cylinder 62, and FIG. 7B shows the configuration of the head unit 24 in a state where it is detached from the air cylinder 62.
As shown in FIG. 7A, the air cylinder 62 has a base portion 62a fixed to the stay 61, and a lift portion 62b (combination member) that moves up and down with respect to the base portion 62a, and is provided in the lift portion 62b. The front end portion 24c of the substrate 24a is inserted into the opening, and the substrate 24a is supported in a state where the elevating unit 62b and the substrate 24a are combined. The air cylinder 62 moves the head unit 24 in a direction away from the clamp 70 when the elevating part 62b is raised in a state where the fixing of the head unit 24 by the clamp 70 is released, and the elevating part 62b is lowered. As a result, the head unit 24 is moved to the attachment position with respect to the clamp 70.
Here, the opening of the elevating part 62b and the front end part 24c of the substrate 24a are not fixed to each other. When the head unit 24 is fixed to the clamp 70, the elevating part 62b exerts a force on the substrate 24a. It is supposed not to affect. That is, the elevating part 62b supports the substrate 24a of the head unit 24 only when moving the head unit 24 released from the clamp 70.

The stay 61 includes a pair of plate-like side frames 61a that each have a base 62a of the air cylinder 62 fixed and extending in the vertical direction, and an upper frame 61b and a lower frame that are spanned between the pair of side frames 61a in the width direction. 61c (frame member). Further, a slide member 61d is provided on the upper surface of the upper frame 61b, and the stay 61 is attached to a guide rail 91 (FIGS. 4 to 6 and the like) extending in the width direction via the slide member 61d. It has been. The guide rail 91 is fixed to a frame member (not shown) of the inkjet recording apparatus 1. With such a configuration, the stay 61 can move in the width direction as the slide member 61 d slides along the guide rail 91. That is, in a state where the fixing of the head unit 24 by the clamp 70 is released and the head unit 24 is separated from the clamp 70, the entire carriage 60 can be moved in the width direction. As a result, the head unit 24 is moved to a predetermined maintenance position, and a maintenance operation such as cleaning of the nozzle surface 24f and an ink discharging operation for preventing ink thickening at the nozzle can be performed. In the present embodiment, the stay 61 and the air cylinder 62 constitute a holding portion that holds the head unit 24 in a state where the fixing of the head unit 24 to the mounting member 212 is released.

Between the U-shaped locking member 61e provided on the lower surface of the lower frame 61c of the stay 61 and the U-shaped locking member 24e provided on the upper surface of the upper housing 24b of the head unit 24, A support member 90 having an elastic body is bridged. The support member 90 of this embodiment is a metal provided between a hook 90a (first part) attached to the locking member 61e and a hook 90b (second part) attached to the locking member 24e. The spring 90c is stretched between the locking member 61e and the locking member 24e in a state where the spring 90c is extended from the natural state. Since the support member 90 can expand and contract in accordance with the lifting and lowering operation of the head unit 24 by the air cylinder 62, the lifting and lowering operation can be performed while the support member 90 is attached. The purpose and operation of providing the support member 90 will be described later.

Next, the fixing mechanism of the head unit 24 by the clamp 70 will be described.
FIG. 8 is a view for explaining a fixing mechanism of the head unit 24 by the clamp 70. In FIG. 8A, the front end portion of the clamp 70 and the engaging portion 80 provided on the lower surface of the substrate 24a of the head unit 24 are shown.

The distal end of the clamp 70 includes a main body 71, a pull rod 72, a cover block 73, an engagement ball 74, a clamp spring 75, a release air supply unit 761, a lock air supply unit 762, and the like.
The pull rod 72 has a cylindrical rod portion 72b extending upward from a base portion 72a disposed in a recess provided in the main body portion 71, and a hollow portion with a gradually decreasing diameter near the tip of the rod portion 72b. 72c is formed.
The cover block 73 has a cylindrical guide portion 73 c through which the rod portion 72 b of the pull rod 72 passes, and is fixed to the main body portion 71 so as to cover the concave portion of the main body portion 71 and the base portion 72 a of the pull rod 72.
The engagement ball 74 is a spherical member disposed in a through hole provided in the guide portion 73 c of the cover block 73.
The clamp spring 75 is housed in a housing portion formed of concave portions facing each other formed inside the base portion 72a of the pull rod 72 and the cover block 73, and an elastic force that separates the pull rod 72 and the cover block 73 in the vertical direction in FIG. Is exerted on the pull rod 72 and the cover block 73.
The pull rod 72 is provided so as to be movable in the vertical direction in FIG. 8 in the space formed by the concave portion of the main body 71 and the cover block 73. That is, the pull rod 72 moves upward in the space by supplying air from the release air supply unit 761 to the bottom of the concave portion of the main body 71, stops the supply of air from the release air supply unit 761 and locks it. By supplying air from the air supply part 762 to the storage part of the clamp spring 75, the air moves downward in the space by the pressure of the air and the elastic force of the clamp spring 75. In addition, when the pull rod 72 is moved upward, the engagement ball 74 is positioned in the recess 72c.

The engaging portion 80 includes a storage portion 81 having a recess in which the rod portion 72 b of the pull rod 72 and the guide portion 73 c of the cover block 73 are stored, and a fixed block 82 provided on the periphery of the recess of the storage portion 81.
The storage portion 81 is formed of a member separate from the substrate 24a, which is attached to the substrate 24a so that the vertical position in FIG. 8A can be adjusted. With such a configuration, the interval between the nozzle surface 24 f and the outer peripheral curved surface 211 a of the transport drum 211 can be adjusted by adjusting the vertical position of the storage portion 81. The storage portion 81 may be formed by processing the substrate 24a of the head unit 24.
A tapered portion 82 b is formed on the inner periphery of the fixed block 82. The tapered portion 82b contacts the tapered portion 73b provided on the outer peripheral surface of the guide portion 73c of the cover block 73 in a state where the clamp 70 and the engaging portion 80 are fixed. The flat seating surface 82a formed by the bottom surface of the fixed block 82 abuts on a flat reference surface 73a provided on the outer surface of the cover block 73 in a state where the clamp 70 and the engaging portion 80 are fixed. . Further, the fixed block 82 is provided with a protruding portion 82c having an inner diameter smaller than that of the tapered portion 82b.

When the clamp 70 and the engaging portion 80 are fixed, as shown in FIG. 8B, air is supplied from the release air supply portion 761 and the pull rod 72 is moved upward. 72 b and the guide part 73 c of the cover block 73 are housed in the recessed part of the housing part 81. At this time, since the engaging ball 74 is located in the recessed portion 72 c, the engaging ball 74 does not protrude from the guide portion 73 c of the cover block 73. Thereby, the engagement ball 74 can pass through the position of the protruding portion 82c of the fixed block 82 upward.

In this state, as shown in FIG. 8C, the supply of air from the release air supply unit 761 is stopped and the supply of air from the lock air supply unit 762 is started, and the pull rod 72 is pulled downward. As a result, the position of the recessed portion 72 c is lowered, and the engagement ball 74 is pushed out to the outside of the guide portion 73 c of the cover block 73 accordingly. At this time, the engaging ball 74 pushes the protruding portion 82c of the fixed block 82 downward, so that the tapered portion 82b contacts the tapered portion 73b and the seating surface 82a contacts the reference surface 73a, At this position, the engaging portion 80 and the clamp 70 are fixed.

FIG. 9 is a schematic side view showing a state in which the four head units 24 are fixed by the clamps 70.
FIG. 10 is a diagram illustrating a positional relationship between the nozzle surface 24 f of the head unit 24 and the outer peripheral curved surface 211 a of the transport drum 211.
Each head unit 24 is fixed in a state where the nozzle surface 24f faces the outer peripheral curved surface 211a above the cylindrical shaft 211b in the vertical direction in a predetermined positional relationship. Specifically, as shown in FIG. 10A, the head unit 24 has the largest variation in the distance d1 between the opening and the outer peripheral curved surface 211a of each of the plurality of nozzles 243 provided at different positions in the transport direction on the nozzle surface 24f. Fixed in a small state. Since the width of the nozzle surface 24f in the transport direction is very small with respect to the length of the outer periphery of the transport drum 211, the portion of the outer peripheral curved surface 211a facing the nozzle surface 24f can be approximated to a plane. Under such an approximation, the head unit 24 is fixed in a state where the nozzle surface 24f and the outer peripheral curved surface 211a are parallel (hereinafter referred to as a parallel state).

Here, as shown in FIG. 9, since the outer peripheral curved surface 211a of the transport drum 211 is a curved surface, the head unit 24 is configured according to the inclination angle of the outer peripheral curved surface 211a at the position where the nozzle surface 24f faces. Fixed in a tilted state from the vertical direction. For example, the head unit 24 corresponding to the rightmost Y in FIG. 9 is perpendicular to the bottom surface on which the nozzle surface 24f is provided, and the center axis passing through the center of the bottom surface and the center of gravity G of the head unit 24 is at an angle with respect to the vertical direction. The head unit 24 corresponding to the second M from the right is fixed in a state inclined by θ1, and the central axis is fixed in a state in which the central axis is inclined by an angle θ2 (<θ1) with respect to the vertical direction.

For this reason, the distance Lg between the center of gravity G of the head unit 24 and the cylindrical shaft 211b in the horizontal distance direction in FIG. 9 that is perpendicular to the cylindrical shaft 211b of the transport drum 211 in the horizontal plane is a fixed position F (engagement portion) by the clamp 70. The position L is greater than the distance Lf between the cylindrical shaft 211b. That is, the fixed position F is between the cylindrical shaft 211b and the center of gravity G in the horizontal distance direction, and the center of gravity G and the fixed position F are shifted in the horizontal distance direction. The fixed position F is located below the center of gravity G in the vertical direction, and is closer to the cylindrical shaft 211b than the center of gravity G. As a result of the arrangement of the head unit 24 in this way, in the head unit 24, a moment is generated due to gravity to rotate the head unit 24 around the fixed position F as the center of rotation. Thereby, depending on the strength of fixing by the clamp 70, the entire head unit 24 may be inclined from the parallel state with the fixing position F as the center. Further, even if the fixing strength by the clamp 70 is sufficient, the intermediate portion of the two fixing positions F in the width direction of the head unit 24 may be bent. The moment generated by gravity in the head unit 24 is represented by the outer product of the position vector of the center of gravity G starting from the fixed position F in FIG. 9 and the vector representing the gravity acting on the head unit 24. In particular, in this embodiment, since the heavy ink tank 24g is accommodated in the upper casing 24b of the head unit 24, the position of the center of gravity G of the head unit 24 is high (that is, the position vector is large), A large moment is generated in the head unit 24 due to gravity. For this reason, the inclination and bending of the head unit 24 described above are likely to occur.

FIG. 10B is a diagram illustrating an example of the positional relationship between the nozzle surface 24f and the outer peripheral curved surface 211a when the head unit 24 is inclined or bent due to gravity. As shown in this figure, when the head unit 24 is inclined or bent, the distance between the nozzle surface 24f and the outer peripheral curved surface 211a is not parallel, that is, depending on the position of the nozzle surface 24f in the transport direction. Will be in different states. As a result, the distance between the opening of the nozzle 243 of the recording head 242 provided at a different position in the transport direction and the outer peripheral curved surface 211a varies depending on the position in the transport direction. For example, in the nozzle 243 on the most downstream side in the transport direction in FIG. 10B, the distance between the nozzle opening and the outer peripheral curved surface 211a is d2, and in the nozzle 243 on the most upstream side in the transport direction, the distance between the nozzle opening and the outer peripheral curved surface 211a. The distance is d3 smaller than d2. When the distance between the nozzle opening and the outer peripheral curved surface 211a varies, the time until the ink ejected from the nozzle 243 lands on the recording medium P on the outer peripheral curved surface 211a varies depending on the distance. It does not land at an appropriate position, leading to a decrease in the image quality of the recorded image.

Therefore, in the present embodiment, as shown in FIGS. 5 and 6, the locking member 24 e provided in the upper casing 24 b of the head unit 24 and the locking member 61 e provided in the lower frame 61 c of the stay 61. A support member 90 having a stretched metal spring 90c is bridged between them. A tensile stress (restoring force) is generated in the spring 90c according to the force received from the hook 90a and the hook 90b, and the lower frame 61c and the upper housing 24b receive a force in the direction in which the relative distance is reduced from the support member 90. Here, since the stay 61 is attached to the guide rail 91 and fixed in position, the head unit 24 receives a force from the support member 90 in a direction that causes the head unit 24 in a direction opposite to the rotation direction due to gravity. In this way, the support member 90 applies a force in a direction that prevents rotation due to gravity to a position farther from the cylindrical shaft 211b than the fixed position F in the head unit 24, thereby supporting the head unit 24. Inclination and bending are suppressed. As a result, the head unit 24 fixed with the central axis tilted from the vertical direction is maintained in the parallel state described above.

The magnitude of the force that the support member 90 exerts on the head unit 24 is adjusted so as to be within a range in which the head unit 24 is maintained in a parallel state by the force. Such adjustment can be performed by changing the elastic body used for the support member 90 to one having a different longitudinal elastic modulus. For example, the head unit 24 having a larger inclination angle from the vertical direction of the central axis of the head unit 24, that is, a mounting method in which a moment that induces rotation of the head unit 24 due to gravity is large with respect to the mounting member 212. A support member 90 having an elastic body with a larger longitudinal elastic coefficient is used for the head unit 24. When the support member 90 includes the spring 90c, the magnitude of the force that the support member 90 exerts on the head unit 24 can be adjusted by using the spring 90c having a different spring constant.
Further, instead of changing the elastic body of the support member 90 or in addition to changing the elastic body, the amount of force that the support member 90 exerts on the head unit 24 by changing the extension amount of the support member 90 from the natural state. Can be adjusted. For example, the locking member 61e of the stay 61 shown in FIG. 6 is configured to be movable in the left-right direction in FIG. 6, and the position of the locking member 61e, that is, the fixing position on the stay 61 side by the hook 90a of the support member 90 is adjusted. By doing so, the magnitude of the tensile stress generated in the support member 90 can be adjusted. The adjustment of the fixing position of the support member 90 may be performed by a human hand, or may be performed by providing a moving mechanism for moving the locking member 61e and controlling the moving mechanism by the CPU 41.

As described above, the ink jet recording apparatus 1 according to this embodiment includes the cylindrical transport drum 211, the recording medium P is placed on the outer peripheral curved surface 211 a of the transport drum 211, and the transport drum 211 is placed on the cylindrical shaft. The relative position of the cylindrical shaft 211b is fixed with the conveyance unit 21 that conveys the recording medium P by rotating around the 211b, the head unit 24 that has the nozzle 243 that ejects ink to the conveyed recording medium P, and the cylindrical shaft 211b. The mounting member to which the head unit 24 is mounted in a state where the outer peripheral curved surface 211a of the transport drum 211 and the opening on the nozzle surface 24f where the opening of the nozzle 243 is provided in the head unit 24 face each other at a predetermined relative distance. 212 and the head unit 24 in the horizontal distance direction perpendicular to the cylindrical axis 211b in the horizontal plane. A clamp 70 that fixes the engaging portion 80 located between the center of gravity G of the unit 24 and the cylindrical shaft 211b to the mounting member 212, and a direction that prevents rotation of the head unit 24 fixed to the mounting member 212 due to gravity. And a support member 90 that applies force to the head unit 24 to support the head unit 24.
According to such a configuration, in the head unit 24 in which the position of the engaging portion 80 and the center of gravity G are shifted in the horizontal distance direction, the head unit 24 is supported by the support member 90, whereby the head unit 24 by gravity is supported. Inclination and bending can be suppressed. Thereby, the fluctuation | variation of the distance of the nozzle surface 24f and the outer peripheral curved surface 211a of the conveyance drum 211 can be suppressed. As a result, the variation in the distance between the opening of the nozzle 243 and the outer peripheral curved surface 211a is suppressed, and the time until the ink ejected from the nozzle 243 lands can be made uniform for each nozzle 243. The image can be recorded with an appropriate image quality.

Further, the support member 90 supports the head unit 24 by exerting a force in a direction that prevents the rotation in a position farther from the cylindrical shaft 211b than the engaging portion 80 in the head unit 24. According to such a configuration, the support member 90 supports the head unit 24 by exerting a force on a position on the center of gravity side of the fixed position F where the engaging portion 80 is provided in the head unit 24, so that the head by gravity is used. The bending of the unit can be effectively suppressed.

In addition, the nozzle surface 24f is provided with openings of a plurality of nozzles 243 over a predetermined recording width in the width direction (cylindrical axis direction). The clamp 70 for fixing the engaging portion 80 located on one side of the arrangement range of the nozzles 243 to the mounting member 212 and the engaging portion 80 located on the other side of the arrangement range of the plurality of nozzles 243 are provided. The support member 90 supports the head unit 24 by exerting a force on a position between the pair of engaging portions 80 in the width direction of the head unit 24. According to such a configuration, it is possible to suppress the occurrence of a problem that the head unit 24 is bent by gravity at the center in the width direction and the distance between the nozzle surface 24f and the outer peripheral curved surface 211a varies.

Further, the openings of the plurality of nozzles 243 on the nozzle surface 24f are opposed to a plurality of different positions on the outer peripheral curved surface 211a in the transport direction. In such a configuration, when the nozzle surface 24f and the outer peripheral curved surface 211a become non-parallel due to the inclination or deflection of the head unit 24 due to gravity, the openings and the outer peripheral curved surface 211a of the plurality of nozzles 243 having different positions in the transport direction are formed. Although the problem that the distance varies occurs, in the present embodiment, by supporting the head unit 24 by the support member 90, the occurrence of the problem can be suppressed.

The head unit 24 includes a recording head 242 having a nozzle surface 24f and a substrate 24a to which the recording head 242 is fixed. The recording head 242 has the nozzle surface 24f exposed from one surface of the substrate 24a. The clamp 70 fixes the engaging portion 80 provided on the one surface of the substrate 24a to the mounting member 212. According to such a configuration, since the head unit 24 is fixed by the engaging portion 80 and the clamp 70 at a position in the vicinity of the nozzle surface 24f, fluctuations in the position of the nozzle surface 24f can be suppressed. Further, in such a configuration, the head unit 24 is fixed at a portion closest to the cylindrical shaft 211b in the head unit 24 or in the vicinity thereof, and thus the distance between the fixing position F and the center of gravity G is increased. For this reason, the moment that induces the rotation of the head unit 24 due to gravity is increased and the head unit 24 is likely to be inclined or bent. However, the support member 90 supports the head unit 24 so that the inclination and the bending are effective. Can be suppressed.

The head unit 24 has an upper casing 24b provided on the opposite side of the one surface of the substrate 24a, and the support member 90 supports the head unit by exerting a force on the upper casing 24b. In such a configuration, the provision of the upper casing 24b tends to increase the distance between the fixed position F of the head unit 24 and the center of gravity G, and the moment that induces the rotation of the head unit 24 due to gravity is further increased. The head unit 24 becomes larger and the head unit 24 is more easily inclined and bent. However, the head member 24 is supported by the support member 90, so that the head unit 24 can be effectively suppressed.

In addition, the upper casing 24b accommodates an ink tank 24g for storing ink supplied to the recording head 242. In such a configuration, the distance between the fixed position F of the head unit 24 and the center of gravity G is further increased, and the moment in the head unit 24 is further increased. Inclination and bending of the head unit 24 can be effectively suppressed.

The support member 90 has a relative position of the hook 90a as the first part of the support member 90 relative to the cylindrical shaft 211b, and the hook 90b as the second part is fixed to the head unit 24. The head unit 24 is supported by a tensile stress generated between 90a and the hook 90b. According to such a configuration, the head unit 24 can be supported in such a manner that a portion of the head unit 24 that is far from the nozzle surface 24f is pulled, so that a space in the vicinity of the head unit 24 opposite to the nozzle surface 24f is formed. The support member 90 can be provided by using it. For this reason, in the inkjet recording apparatus 1 having the plurality of head units 24, the plurality of head units 24 can be arranged closer to each other, and the inkjet recording apparatus 1 can be downsized.

The ink jet recording apparatus 1 also includes a stay 61 and an air cylinder 62 that can hold the head unit 24 at a predetermined relative position with respect to the cylindrical shaft 211b in a state where the fixing of the head unit 24 by the clamp 70 to the mounting member 212 is released. (Holding portion) and the hook 90 a of the support member 90 is attached to the stay 61. More specifically, the elevating part 62b of the air cylinder 62 is combined with the substrate 24a, and the lower frame 61c of the stay 61 is provided integrally with the air cylinder 62 and is positioned above the upper casing 24b in the vertical direction. The stay 61 and the air cylinder 62 support the substrate 24a by the lifting / lowering part 62b of the air cylinder 62 at least in a state where the fixing of the head unit 24 by the clamp 70 with respect to the mounting member 212 is released. The hook 90a of the support member 90 is fixed to the lower frame 61c of the stay 61, and the hook 90b of the support member 90 is fixed to the upper housing 24b. 90 occurs between the hook 90a and the hook 90b. By Zhang stress supports the head unit 24.
According to such a configuration, the support member 90 can be attached using the member that holds the head unit 24 without providing a dedicated member for fixing the hook 90 a of the support member 90. For this reason, the enlargement and cost increase of the inkjet recording apparatus 1 can be suppressed. In addition, the head unit 24 can be fixed to the mounting member 212 and released without removing the support member 90 from the head unit 24 and the stay 61.

Further, the support member 90 has an elastic body that generates a tensile stress according to the force received from the hook 90a and the hook 90b. With such a configuration, the relative position between the member (the stay 61 in the above embodiment) to which the hook 90a of the support member is attached and the head unit 24 to which the hook 90b is attached is, for example, raised and lowered by the air cylinder 62. Even when it fluctuates due to the operation, the support member 90 can be expanded and contracted in accordance with the ascending / descending operation. Therefore, the relative position can be varied without removing the support member 90.

In addition, the inkjet recording apparatus 1 includes a plurality of head units 24 and a plurality of support members 90 corresponding to the plurality of head units 24. An elastic body having a larger longitudinal elastic coefficient is used for the support member 90 corresponding to the head unit 24 that is mounted in a manner that causes a large moment to induce the rotation of the unit 24. Thereby, in the case where the support member 90 is configured to have an elastic body, the inclination and bending of the head unit 24 due to gravity can be appropriately suppressed according to the mounting angle of the head unit 24 with respect to the mounting member 212. .

Note that the present invention is not limited to the above-described embodiments and modifications, and various modifications can be made.
For example, in the above-described embodiment, the support member 90 has been described using an example having the metal spring 90c. However, the support member 90 may be configured using another elastic member made of a resin, a carbon fiber material, or the like. . Further, the support member 90 may be configured by using a member such as a cable made of a material that does not have elasticity or is extremely small, such as metal or carbon steel.

In the above embodiment, the example in which one end of the support member 90 is attached to the stay 61 that is a constituent member of the carriage 60 has been described, but the present invention is not limited to this. The support member 90 may be attached to another member of the inkjet recording apparatus 1 whose relative position with respect to the cylindrical shaft 211b of the transport drum 211 is fixed, for example, a frame member that supports the components of the inkjet recording apparatus 1.

In the above embodiment, the example in which the other end of the support member 90 is attached to the upper surface of the upper housing 24b of the head unit 24 has been described. However, the present invention is not limited thereto, and the other end of the support member 90 is the head unit. It can be attached to any position that can exert a force in a direction that prevents the head unit 24 from rotating due to gravity.

In the above embodiment, the support member 90 has been described using an example in which the support member 90 is detachably fixed to the

locking members

61e and 24e by the

hooks

90a and 90b, respectively. The fixed aspect is not limited to this. For example, one end and the other end of the support member 90 may be fixed to the member to be fixed in another removable manner, or may be fixed to the member to be fixed by adhesion or welding.
Further, the portion of the support member 90 that is fixed to the member to be fixed is not necessarily the end of the support member 90. For example, two different portions between one end and the other end of the spring constituting the support member 90 may be fixed to the member to be fixed. In this case, the interval between the two fixed portions is changed. Thus, the magnitude of the tensile stress generated in the support member 90 can also be adjusted.

Moreover, although the said embodiment demonstrated using the example in which the supporting member 90 was attached to one place of the center part about the width direction among the upper housing | casing 24b of the head unit 24, it is not restricted to this, The one head unit 24 is not limited to this. Two or more support members 90 may be attached.

In the above-described embodiment, the example in which the head unit 24 is pulled and supported by the support member 90 has been described. However, instead of the support member 90 or in addition to the support member 90, the head unit 24 may be mounted. A support member that supports the vertical direction from below may be used. In this case, for example, the head unit 24 can be supported by bringing the spring compressed from the natural state into contact with the head unit 24.

In the above embodiment, the support member 90 that directly contacts the head unit 24 and exerts a force on the head unit 24 has been described as an example. However, the support member does not contact the head unit 24, for example, by a magnetic force. It may be one that exerts a force on the unit 24.

Moreover, although the said embodiment demonstrated using the example where the head unit 24 is fixed in the two fixed positions F located on the line parallel to the cylindrical axis 211b, it is not restricted to this, The line which passes through the fixed position F May be fixed in a manner that is not parallel to the cylindrical shaft 211b. The head unit 24 may be fixed in another manner in which the fixing position F of the head unit 24 (that is, the position of the fixing portion) is between the center of gravity G and the cylindrical shaft 211b in the horizontal distance direction.

Further, the fixing mechanism of the head unit 24 is not limited to the one using the clamp 70 shown in the above embodiment, and other fixing mechanisms such as one using bolts and nuts may be used. Moreover, the fixing location of the head unit 24 is not limited to two locations near both ends in the width direction of the bottom surface, and may be one location or three or more locations. Further, parts other than the bottom surface of the head unit 24 (in the above embodiment, the lower surface of the substrate 24a) may be fixed to the mounting member 212.

In the above embodiment, the head unit 24 can be attached to and detached from the mounting member 212 by the clamp 70. However, the present invention is not limited to this, and the relative position between the head unit and the cylindrical shaft of the transport drum is determined. The present invention may be applied to an inkjet recording apparatus that is always fixed.

Further, the configuration of the head unit is not limited to that described in the above embodiment, and may be any member that is configured integrally with a member provided with a nozzle surface (in the above embodiment, the recording head 242). Any configuration may be used. For example, a configuration in which a substrate on which the recording head is fixed, a frame integrally formed with the substrate, and the like are provided, and a member corresponding to the upper housing 24b in the above-described embodiment may be omitted. In addition, an ink tank may not be provided in the head unit, and ink may be supplied to the recording head from the outside of the head unit. In the above embodiment, the center of gravity G of the head unit 24 is located on the central axis that passes through the center of the bottom surface of the head unit 24 and is perpendicular to the bottom surface. The structure which does not pass a center axis | shaft may be sufficient.

Moreover, although the said embodiment demonstrated using the example in which the nozzle unit 243 from which the position about a conveyance direction differs in the head unit 24 was provided, it is not restricted to this, The head unit 24 is the same about a conveyance direction. You may have a single nozzle row which consists of the some nozzle 243 provided in the position.

In the above embodiment, the configuration in which the portion on the upper side of the outer peripheral curved surface 211a of the transport drum 211 in the vertical direction from the cylindrical shaft 211b and the nozzle surface 24f of the head unit 24 face each other has been described as an example. The present invention may be applied to an ink jet recording apparatus having a configuration in which the lower portion of the outer peripheral curved surface 211a in the vertical direction with respect to the cylindrical shaft 211b faces the nozzle surface 24f of the head unit 24.

In the above-described embodiment, the example in which the cylindrical shaft 211b of the transport drum 211 is horizontal has been described. However, the cylindrical shaft 211b allows ink ejected from the head unit 24 to be printed on the recording medium P on the outer peripheral curved surface 211a. You may incline from the horizontal surface in the range which can be made to land at an appropriate position.

In the above-described embodiment, the ink jet recording apparatus 1 that discharges the ink that is gelled at room temperature and is heated to form a sol when heated is described as an example. However, the present invention is not limited to this. Various known inks including inks that are sol or liquid at room temperature may be used.

Although several embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, and includes the scope of the invention described in the claims and equivalents thereof. .

The present invention can be used for an ink jet recording apparatus.

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 External device 10 Paper feed part 20 Image forming part 21 Conveying part 211 Conveying drum 211a Outer peripheral curved surface 211b Cylindrical shaft 212 Mounting member 22 Delivery unit 23 Heating part 24 Head unit 24a Substrate 24b Upper case

24c Tip part

24d Support Plate

24e Locking member

24f Nozzle surface

24g Ink tank 241 Recording head drive unit 242 Recording head 242M Head module 243 Nozzle 25 Fixing unit 26 Delivery unit 30 Paper discharge unit 40 Control unit 41 CPU
42 RAM
43 ROM
44 Storage Unit 51 Transport Drive Unit 52 Input / Output Interface 53 Bus 60 Carriage 61 Stay

61a Side Frame

61b Upper Frame

61c Lower Frame

61d Slide Member

61e Locking Member 62 Air Cylinder 70 Clamp 80 Engagement Unit 90 Support Member 91 Guide Rail F Fixed Position G Center of gravity P Recording medium

Claims

A transport unit that has a cylindrical transport drum, the recording medium is placed on an outer peripheral curved surface of the transport drum, and transports the recording medium by rotating the transport drum around a cylindrical axis;
A head unit having a nozzle for discharging ink to the recording medium to be conveyed;
The relative position with respect to the cylindrical shaft is fixed, and the outer peripheral curved surface of the transport drum and the opening on the nozzle surface where the opening of the nozzle is provided in the head unit face each other with a predetermined relative distance. An attachment member to which the head unit is attached;
In the head unit, a fixing member that fixes a fixing portion located between the center of gravity of the head unit and the cylindrical shaft in a horizontal plane in a direction perpendicular to the cylindrical shaft, to the mounting member;
A support member that supports the head unit by exerting on the head unit a force in a direction that prevents rotation of the head unit fixed to the mounting member due to gravity;
An ink jet recording apparatus comprising:
2. The inkjet recording according to claim 1, wherein the support member supports the head unit by exerting a force in a direction that prevents the rotation on the head unit at a position farther from the cylindrical shaft than the fixed portion. 3. apparatus.
The nozzle surface is provided with a plurality of nozzle openings over a predetermined recording width in the cylinder axis direction along the cylinder axis,
The ink jet recording apparatus
In the head unit, in the head unit, the first fixing member that fixes the first fixing portion positioned on one side of the arrangement range of the plurality of nozzles in the cylindrical axis direction to the mounting member; The second fixing member that fixes the second fixing portion located on the other side of the arrangement range of the plurality of nozzles in the cylindrical axis direction with respect to the mounting member;
The support member exerts a force on a position between the first fixed portion and the second fixed portion in the cylindrical axis direction of the head unit to support the head unit. The ink jet recording apparatus according to 1 or 2.
The nozzle surface is provided with a plurality of nozzle openings over a predetermined recording width in the cylinder axis direction along the cylinder axis,
The inkjet recording apparatus according to any one of claims 1 to 3, wherein the openings of the plurality of nozzles are opposed to a plurality of different positions on the outer peripheral curved surface in a recording medium conveyance direction.
The head unit is
A recording head having the nozzle surface;
A substrate on which the recording head is fixed;
With
The recording head is fixed to the substrate with the nozzle surface exposed from one surface of the substrate,
The inkjet recording apparatus according to claim 1, wherein the fixing member fixes the fixing portion provided on the one surface of the substrate to the mounting member.
The head unit has a housing provided on the side opposite to the one surface of the substrate,
The ink jet recording apparatus according to claim 5, wherein the support member supports the head unit by exerting a force on the housing.
The ink jet recording apparatus according to claim 6, wherein an ink tank for storing ink supplied to the recording head is accommodated in the casing.
In the support member, a relative position of the first part of the support member with respect to the cylindrical shaft is fixed, and a second part different from the first part is fixed to the head unit, The ink jet recording apparatus according to any one of claims 1 to 7, wherein the head unit is supported by a tensile stress generated between a part and the second part.
A holding portion capable of holding the head unit at a predetermined relative position with respect to the cylindrical shaft at least in a state where the fixing of the head unit by the fixing member to the mounting member is released;
The inkjet recording apparatus according to claim 8, wherein the first part is attached to the holding unit.
A combination member combined with the substrate; and a frame member provided integrally with the combination member and positioned above the casing in the vertical direction, and at least the head by the fixing member with respect to the attachment member A holding unit capable of holding the head unit at a predetermined relative position with respect to the cylindrical axis by supporting the substrate by the combination member in a state in which the unit is released;
The support member has a first position in the support member fixed to the frame member of the holding portion so that a relative position to the cylindrical shaft is fixed, and a second position different from the first position The inkjet recording apparatus according to claim 6 or 7, wherein a part is fixed to the casing and the head unit is supported by a tensile stress generated between the first part and the second part. .
The inkjet recording apparatus according to any one of claims 8 to 10, wherein the support member includes an elastic body that generates the tensile stress in accordance with a force received from the first part and the second part. .
A plurality of the head units;
A plurality of the supporting members corresponding to the plurality of head units;
With
In the plurality of support members, the elastic body having a larger longitudinal elastic coefficient as the support member corresponding to the head unit in which the mounting method is such that a large moment for inducing the rotation of the head unit due to gravity is applied to the mounting member. The inkjet recording apparatus according to claim 11, wherein the inkjet recording apparatus is used.